FMCW radar with additional AM for interference detection

1. A method comprising:

generating a radio frequency (RF) oscillator signal that includes frequency-modulated chirps;

amplitude-modulating the RF oscillator signal by using a modulation signal, representing an identifier code, and a modulation index to obtain an amplitude-modulated RF oscillator signal;

transmitting the amplitude-modulated RF oscillator signal via at least one antenna;

receiving a second RF signal, including frequency-modulated chirp echo signals, from a target object based on transmitting the amplitude-modulated RF oscillator signal;

down-converting the second RF signal into a base band using the RF oscillator signal to obtain a base band signal; and

processing the base band signal to detect information included in the modulation signal.

2. The method of claim 1 , wherein amplitude-modulating the RF oscillator signal comprises:

modulating a respective amplitude of each frequency-modulated chirp, of the frequency-modulated chirps, with the modulation signal.

3. The method of claim 2 , wherein the modulation index is not more than 0.5.

4. The method of claim 1 , wherein the identifier code is a digital word.

5. The method of claim 1 , wherein the modulation signal is a dual level signal or a multi-level signal allowing more than two discrete signal levels.

6. The method of claim 1 , wherein amplitude-modulating the RF oscillator signal comprises:

applying a single side-band modulation to the RF oscillator signal to obtain the amplitude-modulated RF oscillator signal.

7. The method of claim 1 , wherein processing the base band signal comprises:

digitizing the base band signal to obtain a digital signal,

calculating a range map based on the digital signal,

wherein the range map includes a plurality of spectra corresponding to a plurality of chirp echo signals;

detecting one or more peaks in the plurality of spectra indicative of a potential target object;

calculating a time domain signal from the range map for each of the one or more peaks; and

checking whether information included in the modulation signal is also included in the time domain signal.

8. The method of claim 7 , further comprising:

discarding, based on processing the base band signal, the potential target object when the information included in the modulation signal is not included in the time domain signal.

9. The method of claim 1 , wherein processing the base band signal comprises:

correlating a third signal, based on the base band signal, with a forth signal that represents the modulation signal.

10. A radar device comprising:

a radio frequency (RF) oscillator configured to generate an RF oscillator signal that includes frequency-modulated chirps;

a modulator configured to:

receive the RF oscillator signal and a modulation signal representing an identifier code, and

amplitude-modulate the RF oscillator signal using the modulation signal and a modulation index to obtain an amplitude-modulated RF oscillator signal;

one or more antennas configured to:

transmit the amplitude-modulated RF oscillator signal, and

receive a second RF signal including frequency-modulated chirp echo signals from a target object based on transmitting the amplitude-modulated RF oscillator signal;

a mixer configured to:

receive the amplitude-modulated RF oscillator signal and the second RF signal, and

down-convert the second RF signal into a base band to provide a base band signal;

an analog-to-digital converter configured to digitize the base band signal to obtain a digitized base band signal; and

a computing unit configured to process the digitalized base band signal to detect information included in the modulation signal.

11. The radar device of claim 10 , further comprising:

an encoder unit configured to generate the modulation signal based on the identifier code,

wherein the modulator, when amplitude-modulating the RF oscillator signal, is configured to:

modulate each of the frequency-modulated chirps with the modulation signal.

12. The radar device of claim 10 , wherein the modulator is a single side band modulator.

13. The radar device of claim 10 , wherein the computing unit is further configured to:

calculate a range map that includes a plurality of spectra corresponding to a plurality of chirp echo signals;

detect one or more peaks in the plurality of spectra indicative of a potential target object;

calculate a time domain signal from the range map for each of the one or more peaks; and

check whether information included in the modulation signal is also included in the time domain signal.

14. The radar device of claim 13 , wherein the computing unit is further configured to:

discard, based on processing the digitalized base band signal, a potential target object when the information included in the modulation signal is not included in the time domain signal.

15. The radar device of claim 10 , wherein the computing unit is further configured to:

correlate a third signal, based on the base band signal, with a fourth signal that represents the modulation signal.

16. The radar device of claim 10 , wherein at least the RF oscillator and the mixer are integrated in a semiconductor chip.

17. The radar device of claim 10 , wherein the one or more antennas include a single antenna array configured to both receive and transmit signals.

18. The radar device of claim 10 , wherein the one or more antennas are configured to transmit the amplitude-modulated RF oscillator signal in a range from 20 gigahertz (GHz) to 81 GHz.

19. The radar device of claim 10 , wherein the computing unit is a digital signal processor.

20. The radar device of claim 10 , further comprising:

a base band signal processing chain configured to filter and amplify the base band signal and provide the base band signal to the analog-to-digital converter.